This invention relates to a process for preparing bis(hydroxymethyl)methylphosphine oxide.
Tris(hydroymethyl)phosphine (THP) is a hazardous material because of its lability which sometimes leads to expolsions on heating at high temperatures without a solvent. The heating of crude THP at high temperatures is particularly hazardous.
The preparation of bis(hydroxymethyl)methylphosphine oxide by thermally rearranging tris(hydroxymethyl)phosphine in the presence of a solvent such as dimethyl sulfoxide, acetic acid, N-methyl pyrrolidone, N,N-dimethylforamide, and the like, at elevated temperatures, as disclosed by Lin in U.S. Pat. No. 3,732,316, moderates the aforementioned hazard.
In the process of Lin (see Example 1) 40% of the final product composition is tris(hydroxymethyl)phosphine oxide (THPO) when solvent used is dimethyl sulfoxide. When acetic acid is used as the solvent the product is a mixture of various phosphorous compounds containing acetate groups. When N-methyl pyrrolidone is used as the solvent the product composition is 78-79% of bis(hydroxymethyl)methylphosphine oxide and between 21-22% of the THPO.
Thus, there is a need for an improved process which moderates the hazardous lability of tris(hydroxymethyl)phosphine and produces a product having a significantly higher percentage of bis(hydroxymethyl)methylphosphine oxide.
Accordingly, it is an object of the present invention to provide an improved process for preparing bis(hydroxymethyl) -methylphosphine oxide by thermally rearranging tris(hydroxymethyl)phosphine.
It is a further object of this invention to provide an improved process for preparing bis(hydroxymethyl)methylphosphine oxide by thermally rearranging tris(hydroxymethyl)phosphine in an inert solvent.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be realized by practice of the invention, the objects and advantages being realized and attained by means of the methods, processes, instrumentalities and combinations particularly pointed out in the appended claims.